Many car stereo systems (including vehicle computer systems and vehicle entertainment systems) include multiple bands, such as AM, FM1, FM2, and CD. The selected band represents the operating state of the car stereo (e.g., receiving AM stations, receiving FM stations, or playing an audio CD). After selecting a particular band, the user selects a preset button to select between radio stations (or CD in a CD Changer) or a tuning buttons (seek and/or scan) to tune a particular radio station (or select a particular CD track).
Certain vehicle computer systems provide the opportunity to add new features and functions to existing car stereo systems. For example, a vehicle computer system may provide navigational functions in addition to conventional car stereo functions.
As more functions are added to car stereos (or other vehicle computer systems), it may be necessary to add additional buttons to the car stereo to support the new functions. It is important to minimize the number of changes to the current car stereo model to allow the user the easiest adoption path for the new functionality and minimize the negative effects of putting more secondary activities into the car environment. The primary task of a driver of a vehicle is the driving of the vehicle, not manipulating the car stereo controls. Adding a significant number of new buttons to support the new car stereo functions may distract the driver from the primary task of driving the vehicle. Therefore it is important to provide a usability model that is familiar to the user of the car stereo to minimize distractions while driving the vehicle.